Casual games: The secret to Nintendo’s success?

DFC Intelligence by way of Next-Gen has an exhaustive feature exploring the secret to Nintendo’s success, at least on the handheld side of things. They say great casual games pay most of Nintendo’s portable bills.

“Nintendo’s secret – the one that the others don’t quite get – is that it is essentially a maker of casual games. The DS’s success illustrates this perfectly, capturing that most casual of markets – portable gaming – with ruthless efficiency.”

I don’t completely disagree. It’s perhaps one of the biggest differentiators between Nintendo games and others. So are casual games what Nintendo does best?